Which one of the following salts will produce clear and transparent original solution in `2M HCl`?

Options

A. `Ag_(2)CO_(3)`
B. `Pb(CO_(3))_(2)`
C. `Hg_(2)CO_(3)`
D. `CuCO_(3)`

Answer

To determine which salt will produce a clear and transparent solution in 2M HCl, we can analyze the given salts: Ag2CO3, PbCO3, Hg2CO3, and CuCO3.

### Step-by-Step Solution:

1. **Identify the Salts**: The salts given are:
- Ag2CO3 (Silver Carbonate)
- PbCO3 (Lead(II) Carbonate)
- Hg2CO3 (Mercury(I) Carbonate)
- CuCO3 (Copper(II) Carbonate)

2. **Reactions with HCl**: We need to consider how each of these salts reacts with hydrochloric acid (HCl):
- **Ag2CO3 + HCl**: This will produce AgCl (which is insoluble and will form a precipitate) and CO2 gas.
- **PbCO3 + HCl**: This will produce PbCl2 (which is also insoluble in cold water) and CO2 gas.
- **Hg2CO3 + HCl**: This will produce Hg2Cl2 (which is insoluble and will form a precipitate) and CO2 gas.
- **CuCO3 + HCl**: This will produce CuCl2 (which is soluble in water and will remain in solution) and CO2 gas.

3. **Analyzing the Products**:
- For Ag2CO3, PbCO3, and Hg2CO3, the products include insoluble chlorides (AgCl, PbCl2, Hg2Cl2), which will result in a cloudy or opaque solution.
- For CuCO3, the product CuCl2 is soluble in water, leading to a clear and transparent solution.

4. **Conclusion**: Since CuCO3 reacts with 2M HCl to produce CuCl2, which is soluble, the resulting solution will be clear and transparent. Therefore, the correct answer is CuCO3.

### Final Answer:
The salt that will produce a clear and transparent original solution in 2M HCl is **CuCO3**.

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